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The raw materials used to make oolong tea (Camellia sinensis) are a combination of leaf and stem. Oolong tea made from leaf and stem is thought to have a more aromatic smell than leaf-only tea. However, there is no available evidence to support the viewpoint. In this study, sensory evaluation and detailed characterization of emitted and internal volatiles (not readily emitted, but stored in samples) of dry oolong teas and infusions indicated that the presence of stem did not significantly improve the total aroma characteristics. During the enzyme-active processes, volatile monoterpenes and theanine were accumulated more abundantly in stem than in leaf, while jasmine lactone, indole, and trans-nerolidol were lower in stem than in leaf. Tissue-specific aroma-related gene expression and availability of precursors of aroma compounds resulted in different aroma distributions in leaf and stem. This study presents the first determination of the contribution of stem to oolong tea aroma.
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http://dx.doi.org/10.1016/j.foodchem.2017.05.137 | DOI Listing |
Foods
August 2025
Guangdong Provincial Key Laboratory of Nutraceuticals and Functional Foods, College of Food Science, South China Agricultural University, 483 Wushan Street, Tianhe District, Guangzhou 510642, China.
Dancong tea is a representative type of oolong tea typically stored for over six months before sale to reduce gastrointestinal irritation. The effects and mechanisms of this storage on gastrointestinal damage remain unclear. Therefore, this study investigated hydrochloric acid and ethanol (HCl/EtOH)-induced gastric injury in mice.
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August 2025
University of Vigo, Nutrition and Bromatology Group, Department of Analytical Chemistry and Food Science, Faculty of Science, E32004 Ourense, Spain; Research Group on Food, Nutritional Biochemistry and Health, Universidad Europea del Atlántico, Isabel Torres 21, 39011 Santander, Spain. Electronic a
Epigallocatechin gallate (EGCG) is the most abundant polyphenol in tea. Owing to the different fermentation degrees, differences in polyphenol composition of water extracts of green tea, white tea, oolong tea, and black tea occur, and affect health value. This study revealed that the content of EGCG decreases with the increase in the degree of fermentation.
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August 2025
Graduate Institute of Biotechnology, National Chung Hsing University, Taichung, 40227, Taiwan.
Tea, one of the most popular beverages worldwide, is produced from the tender leaves of Camellia sinensis through complex chemical processes. Tea quality is largely determined by its aroma and color, which are influenced by the tea's manufacturing process and cultivar. However, limited research has explored the combined effects of processing methods and tea cultivars on tea infusion color.
View Article and Find Full Text PDFPlants (Basel)
August 2025
Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fuzhou 350007, China.
The impact of seasonality on the aroma quality of tea has been documented in various tea types, but not specifically in oolong tea. This study is the first to explore the complex relationships between seasonality, volatile compounds, and aroma quality in oolong tea. Using Headspace Solid-Phase Microextraction Gas Chromatography-Mass Spectrometry (HS-SPME-GC-MS)-based untargeted metabolomics, we analyzed 266 samples of Tieguanyin oolong tea.
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November 2025
School of Chemical Sciences, The University of Auckland, Auckland, New Zealand. Electronic address:
Free polyfunctional thiols (PFTs) are a class of volatile sulfur-containing compounds known for potent tropical fruit-like aroma notes, even at trace concentrations. In this study, a QuEChERS extraction combined with 4,4'-dithiodipyridine (DTDP) derivatisation enabled simultaneous identification and quantification of three free PFTs (4-methyl-4-sulfanylpentan-2-one, 4MSP; 3-sulfanylhexan-1-ol, 3SH; 3-sulfanylhexyl acetate, 3SHA) and their conjugates (3-S-cysteinylhexan-1-ol, Cys-3SH; 3-S-glutathionylhexan-1-ol, Glut-3SH; and 3-S-γ-glutamylcysteinylhexan-1-ol, γ-GluCys-3SH) by UHPLC-MS/MS in five tea types using isotopically labelled standards. Generally, black tea showed the highest mean concentrations of conjugates (Cys-3SH at 472 ng/g, Glut-3SH at 14430 ng/g, γ-GluCys-3SH at 277 ng/g), while oolong tea exhibited the highest mean concentrations of free PFTs (4MSP at 15 ng/g, 3SH at 36 ng/g, 3SHA at 0.
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